Rock drill



Sept. 22, 1942. J. c. CURTIS Ro'cx DRILL Filed Nov. 16, 1959 2 sheets-sheet 1 Spt. 22, 1942. J. c. CURTIS ROCK DRILL 7 Filed Nov. 16, 1959 2 Sheets-Sheet 2 Patented Sept. 22, 1942 John C- livan Massachusetts Application November 16, 1939. Serial This invention relates to rock drills, and more particularly, but not exclusively, to improvements in a hammer rock drill of the self-supporting stoper type, including improved means for supporting, guiding and feeding the drill steel actuating motor.

An object of this invention is to provide an improved rock drill having improved supporting means for Supporting and guiding a drill steel actuating motor in an improved manner with respect to the work, together with improved feeding means associated with the supporting means for effecting feed of the steel actuating motor. Another object is to provide an improved rock drill of the self-supporting stoper type having improved means for supporting the drill on the working face as well as at its rear end abutment, so that an extremely stable support is attained. A further object is to provide in a rock drill of the stoper type improved means for supporting and guiding the drill steel actuating motor whereby the drill steel is at all times maintained against appreciable lateral displacement, resulting in a straight hole under all drilling conditions. Still another object is to proved extensible sup-porting structure for a rock drill on which the latter is guided and embodying fluid actuated means for extending the supporting structure, together with improved fluid actuated means for feeding the drill steel actuating motor relative to said supporting structure. A still further object is to provide in a supporting structure of the above character, improved fluid actuated means for retracting the drill supporting structure from extraneous abutments after the drill has completed its work. Other objects and advantages of the invention will hereinafter more fully appear in the course of the following description and as more particularly pointed out in the appended claims.

In the accompanying drawings there are shown for purposes of illustration two forms which the invention may assume in practice.

'In these drawings:

Fig. 1 is a side elevational view of a rock drill supported in drilling position supporting, guiding and feeding structure.

Fig. 2 is a view in longitudinal verticalsection showing the improved supporting, guidingand feeding structure in drill steel actuating motor being .shown in side elevation to simplify illustration.

'Fig. '3 is a view similar to :Fig.;2,,sh owing the supporting, guiding and feeding structure in its extended position.

provide an imits collapsed position, the

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ass r 5. ommsm by the .improved proved supporting,

has 1 jo t therein abore l3" havingairear head [4 and containing a ti ,piston rod ll through a packing piston to. The ar n ste r Fig. 4 is an enlarged view, taken in theplane of Fig. 2, showing details of the supporting, guiding. and feeding structure.

Fig. 5. is an enlarged sectional view similar to Fig. 4 showing a modificaton of the invention.

Fig. 6. is an enlarged cross-sectional view taken substantially on line 6-6 of- Fig: l, with parts broken away.

Fig. '7 is a vertical sectional view taken substantially on line. 1-1 of Fig. 6.

Fig. 8 "is a detail sectional view taken in the plane of Fig. 7, showing thecontro-l valve in a different position' Fig. 9 is an enlarged detail sectional view of the control valve taken on the line 9-9 of Fig. 7.

Fig. 10 is a detail vertical sectional view taken substantially on line 10-40 of Fig. 6.

Referring to the drawings, and first particularly to Figs. 1 to 3, inclusive, it will be noted that the drill steel actuating motor is generally designated l and the improved'supporting, guiding and feeding structure is generally designated 2. "The rock drill is herein offlthe selfsupporting stoper type; although it will be evident that various features of the invention may be embodied in rock drills'of various other types. "Ihedrillsteel actuating motor is of the conventional reciprocating piston, hammer type comprising a niotor cylinder 3 containing-a usual 'reciprocatory hammer piston for delivering blows to the shank of a drill steel 4 suitably supported within a front chuck housing 5. The motor cylinder has a usual rear head block 6 containing a control valve mechanism generally designated :I. The rear head block and front chuck housing are suitably secured to the motor cylinder in any conventional manner, as by usual "side rods 8. As the internalistructure of the steel actuating motor and the mode of operation thereof are well known to those skilled in the art, detailed description and illustration of the same are herein unnecessary.

Now referring to the preferred form of the imguiding and feedin structure 2 shown in ,Fig.f1,,it will benoted that contained .in a tubular.feedcylinder 9 is a reciprocablefe ed piston IIIhavinga tubular piston rod II. This piston 'rod extends'rea wardly through a rear feed C li der 9 and has formed 'r eciprocable'piston [5 "having its piston arranged with respect to .and' extending forwardly l1 SlIDDOItGd Within'the f'ee'd actuating motor is rod l6 telescopically mounted on the feed cylinder 9 in parallel relation to the piston rods, and, in this instance, the front chuck housing 5 has a laterally located, integral boss-like portion l8 formed with a bore l9, and the forward end of the feed cylinder 9 is received in the bore l9 and is provided with a front flange 2|) engaging the forward surface of the boss-like member l8. Arranged in the forward end of the feed cylinder 9 is a cylinder head block 2| having a flange 22 engaging the flange 29 and held in position by means of a block 23 abutting the forward surface of the head block 2|. The flange 20, the head block 2| and the block 23 are rigidly attached to the boss-like member |8 by means of side bolts 24. Arranged within the block 23 are cup leathers 25 held in fluid-tight sealing engagement with the exterior surface of the piston rod l6. It will be evident that the cup leathers may be readily replaced when worn simply by releasing the bolts 24 and removing the block 23. Formed in the rearward portion of the head block 2| is a bore 21 for receiving a reduced portion 28 of the feed piston when the feed piston is in its extreme forward position, and an annular groove 29 adjacent the rearward end of the bore 21 receives a snap ring 30 supported by the reduced portion of the piston for holding the piston in its forward position. A small passage 3| in the feed piston I0 connects the bore of the feed cylinder 9 at the forward side of the piston ID with the bore |3 of the piston rod Extending axially through the piston I5 is a bore 33 connecting the bore |3 at the rear side of piston |5 with a smaller bore 34 opening into a chamber 35 extending longitudinally of the piston rod IS. A passage 36 in the piston rod l6 connects the bore 3 of the piston rod II with the space at the junction of the bores 33 and 34. A valve member 31 having a piston portion 38 fitting the bore 33 and another portion 39 fitting the bore 34 controls communication between the passage 36 and the chamber 35. A pin 40 extending transversely of the bore 33 limits the movement of the valve member in its rearward direction and the shoulder at the junction of the bores 33 and 34 limits the forward movement of the valve member. Formed in the side of the valve portion 39 is a, groove 42 providing communication between the passage 36 and the chamber 35 when the valve member is in its forward position. A vent passage 43 in the piston rod |6 connects the forward end of chamber 35 to atmosphere. A vent passage 44 in the feed cylinder 9 near its rearward end provides an escape for pressure fluid that may leak past the feed piston I8. rod I6 is provided with an abutment engaging member 46, while secured to the rear head I4 at the rear end of the piston rod is an abutment engaging point 41, these abutments arranged in alinement with the axes of the piston rods and I6 and adapted to engage suitable extraneous abutments at the opposite ends of the drill.

The throttle valve mechanism 7 comprises a control valve arranged in a valve bore 5| extending transversely of the rear head block 6. Formed in one end of the valve are stepped bores 52 and 53, and a beveled surface 54 at the junction of the bores provides a seat for a valve 55 which reciprocates in the bore 52 and which is continuously urged toward its seated position by a spring 56 supported at one end by a plug 51 screwed into the end of the valve bore. The spring 56 extends into the valve 55 through a passage 55 which opens into a passage 55" extending transversely of the valve 56. The other The forward end of the piston end of the control valve 56 projects from the side of the head block 6 and provides a portion 58 on which a handle 59 is fitted for manual operation of the valve. Formed in the outer surface of the valve is a groove 60 connected by a passage 6| to a passage 62 extending axially through the projecting portion 58 to atmosphere. A groove 64 in the outer surface of the valve connects the space in the end of the valve bore adjacent the plug 51, when the valve is in the position shown in Fig. '7, with a passage 65 in the head block 6 leading to a connection 6'! that opens into a chamber 68 commuincating with the cylinder bore |3 at the rear end of the piston l5. When the valve is in the position shown in Fig. 8 the passage 65 is connected to atmosphere through the groove 60 and passages 6| and 62. Arranged in a bore 69 extending transversely of the head block 6 and parallel to the valve bore 5| is a throttle valve H! for controlling the flow of pressure fluid from a supply connection II to the rock drill actuating motor through a passage 72 or a passage 13 and to the bore of the feed cylinder 9 at the forward side of the feed piston l9. Passages I4 and 14' extending radially through the valve 16 open, when the valve is in position to effect supply of pressure fluid to the drill mo tor through passages 72 and 13 respectively, into a passage 75 formed in the motor cylinder 3 whichv communicates with a passage 16 in the boss-like member l8 that connects with a passage H in the feed cylinder 9 opening into the bore of that cylinder adjacent the rearward end of the head block 2|. A groove 18 formed in the outer periphery of the valve 10 connects the passage 15 to vent through the drill motor when the valve 16 is in a position to cut off supply to the drill motor. Extending radially through the control valve 59 is a passage 19 opening into the bore 53 and communicating, when the valve is in the position shown in Fig. 7, with a passage in the head block 6 that leads to a space 8| in the valve bore 69 to which pressure fluid is supplied from the connection Formed in the outer peripheral surfaces of the valves 50 and 10 are detents 82 and 83, and plungers 84 and 85 reciprocably mounted in a bore 86 in the head block 6 are urged by a spring 81 to engage the detents and hold the valves in their adjusted positions.

The mode of operation of this embodiment of the invention will be clearly apparent from the description given. The drill is operated in the manner of a conventional stoper drill with the rear end abutment point engaging a suitable abutment. When the drill steel is properly positioned with respect to the working face, the operator grasps the handle 59 and rotates the valve 50 into the position shown in Fig. '7. Pressure fluid then flows from the supply connection through passage 80 in the head block 6 and passage 19 in valve 58 to the bore 53 where it acts on valve 55 to move it from its seat against the force of spring 56. When valve 55 is moved from its seat, pressure fluid flows around the end of the valve and through passages 55" and 55 to the end of the valve bore adjacent the plug 51 and through groove 64 to passage 65 that communicates through connection 6'! with the chamber 68 at the rearward end of piston l5. The pressure fluid acting on the rear pressure area of the piston I5 effects movement of the latter forwardly within the cylinder bore |3 until the abutment engaging member 46 engages the working face, so that the rock drill is firmly supported at its opposite ends at remotely spaced points. The operator then rotates valve I into the position shown in Figs. '7 and 110 to supply pressure fluid to the drill motor from the supply connection II through passage I2 and tow supply pressure fluid through passage I4, passage I in the motor cylinder and passage 16,. to the forward end of the feed cylinder 9 where it acts, on the rear pressure area of the head block 2;I and effects movement of the feed cylinder 9 forwardly relative to the piston rods II and I6, and the drill steel actuating motor mounted on the feed cylinder 9 moves forwardly therewith to effect feeding of the drill steel toward the work. During the feeding of the drill steel toward the work there is a restricted flow of pressure fluid from the feed cylinder 9 through the passage 3| in the feed piston III to the bore I3 in the piston rod II, but, since pressure acting on the rear surface of piston I5 also acts on the valve 31 to hold it in its forward open position, there will be a venting of pressure fluid from the bore I3 through passages 36, chamber 35 and passage 43 to atmosphere. The passage 3I will be sufflciently restricted to prevent an appreciable decrease in the feeding pressure on the rearward surface of the head block Ill, and the escape of pressure fluid through passage 36, chamber 35 and passage 43 will be sufficient to prevent a substantial pressure from building up in bore I3. When it is desired to move the drill in a direction away from the work, the operator rotates the valve III to shut off the supply of pressure fluid to the drill motor and to connect groove 18 with passage I5, thereby venting the feed cylinder 9 through passages 11, I6, I5, groove 18 and the drill motor exhaust. The pressure in the feed cylinder between the feed piston I0 and the head block 2| is also vented to atmosphere through passage 3I, cylinder bore I3, passage 36, chamber 35 and passage 43. If it is desired to disengage the member 46 from the working face the control valve 59 is rotated into the position shown in Fig. 8 to cut off the supply of pressure fluid to connection 61 and tovent pressure from the cylinder bore I3 at the rear side of piston I5 through connection 61, passage 65, groove 60 and passages BI and 62. The operator then rotates valve I0 into the position shown in Fig. '7 to supply pressure fluid to the feed cylinder 9 through passages 14, I5, I6 and TI. The pressure fluid acts on the feed piston I0 and the cylinder head 2| to urge the drill motor toward the work but at the same time pressure fluid flows through passage 3I in the feed piston I9, bore I3 in the piston rod I I and passage 36 to the junction of the valve bores 33 and 34 where it acts on the shoulder between the valve portions 33 and 39 to move the valve 31 rearwardly to its closed position. With the valve 31 closed flow of fluid to the vent 43 is cut off, and, as a result, a pressure builds up in the cylinder bore I3 and acts on the forward surface of the piston I5 to move the abutment member 46 away from the working face. Since the combined weight of the piston I5, piston rod I6 and the abutment member 46 is much smaller than that of the drill motor and feed cylinder, the member 43 will be moved away from the working face much faster than the drill motor moves toward the working face, even though the pressure area on the forward side of piston I5 is less than the pressure area effecting the forward feed of the drill.

Referring to the modification of the improved supporting, guiding and. feeding structure shown in Fig. 5, it will be noted that the. packing IgI', shown in Fig. 4., has been eliminated. and that pressure fluid flows from the forward end of the feed cylinder 9 through an annular space v89- between thefeed piston I9 and. the piston rod I6 to the cylinder bore I3. In this; modification, the bore I3 is continuously connected to atmosphere through a passage 90, chamber 35,- in the piston rod I6 and vent passage 43., The, passage 90 is restricted to cause a pressure to exist in the bore I3 while. pressure fluid is: being supplied to the forward end of the feed cylinder 9., The pressure in bore I3 is substantially less than line pressure and. its action on the forward end of piston l5, exposed to the borev I3, is insufficient to prevent line pressure acting on the entire area of piston I5. at the rearward end from holding the abutment engaging member 46. firmly against the face of the work. However, if valve 50 is rotated to a position to vent pressure fluid from the rear surface of piston I5, and pressure fluid is supplied to the forward end of the feed cylinder and to bore I3, the pressure acting on the forward surface. of piston I5. will move that piston rearwardly relative to piston rod II and disengage the member 46 from the working face.

As a result of this invention, it will be noted that an improved: rock drill is provided having improved supporting and guiding means for the drill steel actuating motor whereby the drill is supported at i'ts'rear end and at the working face. It will further be noted that by the provision of telescopically arranged, relatively movable piston rods, an improved supporting structure for a rock drill is provided whereby members may be caused to engage abutments to firmly support the drill during drilling operations, or may be moved from engagement with the abutments to release the support and to remove the drill from the work.

While there are in this application specifically described two forms which the invention may assume in practice, it will be understood that these forms of the same are shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a rock drill, in combination, a drill steel actuating motor, an adjustable supporting structure on which said actuating motor is guided for movement toward and from the face of the work to be drilled, said supporting structure including a movable supporting element engageable with the working face and having apiston fixed thereto, means for subjecting an area on said piston to pressure fluid for effecting movement of said supporting element into engagement with the working face, means for subjecting an oppositely directed area on said piston to pressure fluid for effecting movement of said supporting element away from the working face, means for venting pressure fluid from said first mentioned area on said piston, means for venting pressure fluid from said second mentioned area on said piston, and valve means responsive to the pressures at said first mentioned area for controlling the venting of pressure fluid from said second mentioned area.

2 In a rock drill, in combination, a drill steel actuating motor, an adjustable supporting structure on which said actuating motor is guided for movement toward and from the face of the work to be drilled, said supporting structure including a movable supporting element terminating at its outer end in a point engageable with the working face and having at its inner end a piston, means for subjecting an area on said piston to pressure fluid for moving said supporting element into engagement with the working face, means for subjecting an oppositely directed area on said piston to pressure fluid for moving said supporting element away from the working face, means for venting pressure fluid from said oppositely directed area, and valve means for controlling said venting and held in open position by pressure fluid supplied to said first mentioned area.

3. In a rock drill, in combination, a drill steel actuating motor, an adjustable supporting structure on which said actuating motor is guided for movement toward and from the face of the work to be drilled, said supporting structure including a movable supporting element terminating at its outer end in a point engageable with the working face and having at its inner end a piston, means for subjecting an area on said piston to pressure fluid for moving said supporting element into engagement with the working face, means actuated by pressure fluid for feeding said actuating motor along said supporting structure, means for subjecting a smaller oppositely directed area on said piston to pressure fluid durin the supply of pressure fluid to said fluid actuated feeding means, means for venting pressure fluid from said first mentioned piston area, means for venting pressure fluid from said oppositely directed area, and valve means for controlling the venting of pressure fluid from said'oppositely directed area, said valve means comprising a valve element having areas subjected to the pressures at the opposite areas on said piston and held in open position by pressure fluid supplied to the first mentioned piston area.

4. In a rock drill, in combination, a drill steel actuating motor, an adjustable supporting struc- 1 ture on which said actuating motor is guided for movement toward and from the face of the work to be drilled, said supporting structure including a movable supporting element terminating at its outer end in a point engageable with the working face and having at its inner end a piston, means for subjecting an area on said piston to pressure fluid for moving said supporting element into engagement with the working face, means for subjecting an oppositely directed area on said piston to pressure fluid for moving said supporting element away from the working face, means for venting pressure fluid from said first mentioned piston area, means for venting pressure fluid from said oppositely directed area when pressure fluid is supplied to said first mentioned area, said last mentioned means including a valve having a pressure area subjected to the pressures at said first mentioned piston area and a smaller opposing area subjected to the pressures at said oppositely directed piston area.

5. In a rock drill, in combination, a drill steel actuating motor, an adjustable supporting structure on which said actuating motor is guided for movement toward and from the face of the work to be drilled, fluid actuated means for feeding said motor along said supporting structure, said supporting structure including a supporting element terminating at its outer end in a point engageable with the working face and having at its inner end a piston, means for subjecting an area on said piston to pressure fluid for moving said supporting element into engagement with the working face, means for subjecting a smaller oppositely directed area on said piston to pressure fluid simultaneously with the supply of pressure fluid to said fluid actuated feeding means, and means for venting pressure fluid from said areas on said piston.

6. In a rock drill, in combination, a drill steel actuating motor, an adjustable supporting structure on which said actuating motor is guided for movement toward and from the face of the work to b drilled, fluid actuated means for feeding said motor along said supporting structure, said supporting structure including a supporting element terminating at its outer end in a member engageable with the working face and having at its inner end a piston and said supporting structure further including a cylinder containing said piston, means for supplying pressure fluid to said cylinder for subjecting an area on aid piston to pressure fluid for moving said supporting element to bring said member into engagement with the working face, means for supplying pressure fluid to another part of said cylinder for subjecting a smaller, oppositely directed area on said piston to pressure fluid simultaneously with the supply of pressure fluid to said fluid actuated feeding means, and means for venting from said cylinder pressure fluid acting on the first mentioned one of said areas on said piston to enable the pressure acting on said smaller, oppositely directed area on said piston to retract said member which is engageable with the working face.

JOHN C. CURTIS.

CERTIFICATE OF CORRECTION.

Patent no'. 2,296,818.

JOHN c. cmms.

September 22, 19l+2.'

It -.is herebycertified that error appears -in the printed specification of the above mzmbered patent requiring correction as follows: Page 2, first column, line "(5, strike out. the number "50"; and second column, line 5, otter valve insert --50--; line 15, for "commuincating" read-mommicitin and that the said Letters Patent should he read with this corre c tion therein tha lt the same may conform to the record of the casc in the'Patent Office.

Signed and sealed this 20th day of April, A. D. 19145.

Henry van Arsdale, (Seal) Acting Commissioner of Patents. 

